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Graphene
- Thread starter Wendy
- Start date
http://www.physorg.com/news/2011-07-graphene-secrets.htmlGraphene gives up more of its secrets
Filler information about graphene.
Filler information about graphene.
Hello,
In this article they are mentioning GraphExeter:
http://www.bitsofscience.org/graphene-graphexter-electronics-nano-5783/
Bertus
In this article they are mentioning GraphExeter:
http://www.bitsofscience.org/graphene-graphexter-electronics-nano-5783/
Bertus
Graphene-based terahertz devices: The wave of the future
All these articles, and still no graphene devices. When they hit it will be by a storm.
All these articles, and still no graphene devices. When they hit it will be by a storm.
This is an article I found in Science Digest last year on the subject of Graphene. Enjoy
High hopes are pinned on the new material: Graphene, a honeycomb-like carbon structure, made of only one layer of atoms, exhibits remarkable properties.
In 2010, the Nobel Prize was awarded for the discovery of graphene and its behavior. At the Photonics Institute at the TU Vienna, the electronic and optical properties of graphene are the focus of interest. Viennese scientists could now demonstrate how remarkably fast graphene converts light pulses into electrical signals. This could considerably improve date exchange between computers.
Converting Light into Electrical Signals When data is transmitted by light pulses (for in stance in fiber optic cables) the pulses have to be converted back into electrical signals, which can be processed by a computer. This conversion of light into electrical current is possible due to the photoelectric effect, which was originally explained by Albert Einstein.
In certain materials, light can cause electrons to leave their positions and travel through the material freely, whereby electrical current occurs. "Light detectors which convert light into electronic signals have been around for a long time. But when they are made of graphene, they react faster than most other materials could," Alexander Urich explains. He investigated the optical and electronic properties of graphene together with Thomas Müller and Professor Karl Unterrainer at TU Vienna.
Analysis using Ultra Short Laser Pulses The scientists had already shown last year that graphene can convert light into electronic signals with remarkable speed. However, the reaction time of the material could not be determined -- the photoelectric effect in graphene is so fast that it just cannot be measured by the usual measuring methods. But now, sophisticated technological tricks could shed some light on the properties of graphene.
At TU Vienna, laser pulses were fired at the graphene photo-detector in quick succession, and the resulting photo-current was measured. If the time delay between the laser pulses is changed, the detector's maximum frequency can be determined. "Using this method we could show that our detectors can be used up to a frequency of 262 GHz," Thomas Müller (TU Vienna) says. This corresponds to a theoretical upper bound for data transfer using graphene photo-detectors of more than 30 gigabytes per second. It has yet to be determined to what extent this is technically feasible, but this result clearly shows the remarkable capability of graphene and its potential for optoelectronic applications.
Fast Signals for Fast Electronics The main reason for the fact that graphene-photodetectors can operate at such high frequencies is the short life-span of the charge carriers in graphene. The electrons which are removed from their fixed position and contribute to the electrical current settle down at another fixed position after a few picoseconds (millionths of a billionth of a second, 10E-12 seconds). As soon as this happens, the graphene photodetector is ready for another light signal which frees new electrons, creating the next electrical signal. The fast reaction time of graphene is one more item on the list of remarkable properties of this material. In graphene, charge carriers can travel extremely far without being disturbed. It can absorb light in a huge spectral range, from infrared to visible light -- unlike standard semiconductors, which can only absorb a small part of the spectrum. In addition to this, graphene can conduct heat extremely well and has an exceptionally high breaking strength.
High hopes are pinned on the new material: Graphene, a honeycomb-like carbon structure, made of only one layer of atoms, exhibits remarkable properties.
In 2010, the Nobel Prize was awarded for the discovery of graphene and its behavior. At the Photonics Institute at the TU Vienna, the electronic and optical properties of graphene are the focus of interest. Viennese scientists could now demonstrate how remarkably fast graphene converts light pulses into electrical signals. This could considerably improve date exchange between computers.
Converting Light into Electrical Signals When data is transmitted by light pulses (for in stance in fiber optic cables) the pulses have to be converted back into electrical signals, which can be processed by a computer. This conversion of light into electrical current is possible due to the photoelectric effect, which was originally explained by Albert Einstein.
In certain materials, light can cause electrons to leave their positions and travel through the material freely, whereby electrical current occurs. "Light detectors which convert light into electronic signals have been around for a long time. But when they are made of graphene, they react faster than most other materials could," Alexander Urich explains. He investigated the optical and electronic properties of graphene together with Thomas Müller and Professor Karl Unterrainer at TU Vienna.
Analysis using Ultra Short Laser Pulses The scientists had already shown last year that graphene can convert light into electronic signals with remarkable speed. However, the reaction time of the material could not be determined -- the photoelectric effect in graphene is so fast that it just cannot be measured by the usual measuring methods. But now, sophisticated technological tricks could shed some light on the properties of graphene.
At TU Vienna, laser pulses were fired at the graphene photo-detector in quick succession, and the resulting photo-current was measured. If the time delay between the laser pulses is changed, the detector's maximum frequency can be determined. "Using this method we could show that our detectors can be used up to a frequency of 262 GHz," Thomas Müller (TU Vienna) says. This corresponds to a theoretical upper bound for data transfer using graphene photo-detectors of more than 30 gigabytes per second. It has yet to be determined to what extent this is technically feasible, but this result clearly shows the remarkable capability of graphene and its potential for optoelectronic applications.
Fast Signals for Fast Electronics The main reason for the fact that graphene-photodetectors can operate at such high frequencies is the short life-span of the charge carriers in graphene. The electrons which are removed from their fixed position and contribute to the electrical current settle down at another fixed position after a few picoseconds (millionths of a billionth of a second, 10E-12 seconds). As soon as this happens, the graphene photodetector is ready for another light signal which frees new electrons, creating the next electrical signal. The fast reaction time of graphene is one more item on the list of remarkable properties of this material. In graphene, charge carriers can travel extremely far without being disturbed. It can absorb light in a huge spectral range, from infrared to visible light -- unlike standard semiconductors, which can only absorb a small part of the spectrum. In addition to this, graphene can conduct heat extremely well and has an exceptionally high breaking strength.
Graphene researchers make a layer cake with atomic precision
Of course, I'm still waiting and hoping on the room temperature graphic doping story. See the Superconductor thread.
Of course, I'm still waiting and hoping on the room temperature graphic doping story. See the Superconductor thread.
SplitInfinity
- Joined Mar 3, 2013
- 423
Bill...I happen to find this...http://www.technologyreview.com/vie...eaker-easily-outperforms-traditional-designs/
Now for years they have been attempting to make speakers smaller to do the job larger speaker do and to a point they have done this. Bose has done a good job along with a few other groups but I can tell you that when it comes to Pro-PA Sound...with the exception of the New Design Kicker Box Modules we have...nothing that has been made or designed at a reasonable cost...and I am talking no greater than $1500.00 for a single 18 inch speaker...NOT THE CABINET or the cable connects...but just the speaker.
Years ago they used to make CERAMIC SPEAKERS and they were absolutely fantastic...but not something you would want to use when cold as they take some time to warm up as well as brittle issues.
Bose came out with smaller PA-Systems which were expensive but reasonable...but they just could not push the required Air Mass needed to punch sound through a lot of human bodies filling a stadium.
We currently use JBL SRX-3 Pro Line Speakers as well as all JBL Horns and Drivers. We use many JBL 18 Inch Speakers but we also use the Kickers as well.
The issue is the huge amount of weight and time to set up as well as theft, repair, trucking costs, Union issues, inadequate over seas Power Supplies which we invested a while back into what I can describe as a system of Giant Capacitors which regulates drop offs in power supply....but it would be FANTASTIC if someone developed a Pro-Speaker that could do what the Big Ones and in the not too distant past...we would use 2 JBL 18's in reverse throw cabinets...the speakers point the opposite way one would think and use these cabinet designs to throw massive amounts of Kinetic Force by air movement....Damn things were Huge and weighed a ton.
Now I have heard every argument where someone is telling me that this New Design is smaller and better but everytime...it comes up short...then I read this article on the link provided....interesting.
Split Infinity
Hello,
Here is a page where they claim to have light sensor that are 1000 X more sensitive than regular cmos or ccd sensors by using graphene:
http://www.sciencedaily.com/releases/2013/05/130530094624.htm
Bertus
Here is a page where they claim to have light sensor that are 1000 X more sensitive than regular cmos or ccd sensors by using graphene:
http://www.sciencedaily.com/releases/2013/05/130530094624.htm
Bertus
not as knowledgeable as you guys....but I take it after looking at Bills links......swithces on the atomic scale.....is that the jest of this graphene stuff.
Will somebody summerize the importance of these graphene articles for us underlings....?
In any event....Looks like Im gonna have to get a smaller soldering iron....
and a better pair of bifocals
D.
Will somebody summerize the importance of these graphene articles for us underlings....?
In any event....Looks like Im gonna have to get a smaller soldering iron....
and a better pair of bifocals
D.
What you are seeing is an earth shaking technology as it is developed. Graphene is not quite ready for prime time, but when we get it down it will make orbital bean stalks (which requires lightweight super strength materials beyond anything we have now, such as monofiliments) to ultra fast semiconductors to possibly room temperature superconductors. Not many people in history has got to see this in their lifetimes. I've been lucky enough to see several, electronics (which created home computers) and the space age. God, I'm old!
Another nice application of graphene:
Flexible Touch Screen Made with Printed Graphene
Flexible Touch Screen Made with Printed Graphene
http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=131167&org=NSF&from=news
Seems they are in a fix about heat removal. Plain graphite has very good high temperature thermal properties in inert conditions (we use in to build plasma arc chambers and beam electrodes in vacuum). It seems there is a boundary condition that reflects heat energy back into the Graphene instead of radiating into the substrate.
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